Hydraulic load manipulating mechanism for industrial trucks



Aug. 10, 1954 Filed Sept 13, 1950 B. ULINSKI 2,685,976 HYDRAULIC LOAD MANIPULATING MECHANISM FOR INDUSTRIAL TRUCKS 3 Sheets-Sheet 1 INVENTOR 8.1 (/l/LIJi/ BY ATTORNEY v i in 5 Sheets-Sheet 2 I. ULINSKI MANIPULATING MECHANISM B. HYDRAULIC LOAD FOR INDUSTRIAL TRUCKS mm l Aug. 10, 1954 Filed Sept. 13, 1950 INVENTOR 6A2: Q/ui/li) BY M di-v.

ATTORNEY Aug. 10, 1954 s. ULINSKI HYDRAULIC LOAD MANIPULATING MECHANISM FOR INDUSTRIAL TRUCKS 3 She ets-Sheet 5 Filed Sept. 13, 1950 mm mm 0 8 a on- 5- we f mm cm 3 no g RH mm N r 5 N 1r a ATTORNEY Patented Aug. 10, 1954 HYDRAULIC LOAD MANIPULATING MECH- ANISM FOR INDUSTRIAL TRUCKS Bronislaus I. Ulinski, Chicago, Ill., assignor to The Yale &j Towne Manufacturing Company, Stamford, Conn., a corporation of Connecticut Application September 13, 1950, Serial No. 184,571

10 Claims. I

My invention relates to industrial trucks of the type having a load lifting member mounted for elevating movement thereon and equipped with means for manipulating the load relatively to the truck or for gripping the load through utilization of the weight of the load.

It has been the custom in the prior art to utilize power means for directly moving, gripping or shifting a load or load engaging member, such power means being of direct-acting mechanical, hydraulic, and other suitable type. In my invention, I employ a power means that applies the weight of the load lifting member, with or without a load thereon, to a hydraulic mechanism for laterally shifting or otherwise manipulating said load lifting member.

A feature of my invention resides in the directing of fluid from a power storage ram to another ram for moving a load engaging or load gripping member into proper load engaging position, the pressure of the fluid in said power storage ram being developed by the weight of the load engaging member and the weight of the load applied to the load engaging member.

A further feature of my invention resides in a fork shifting mechanism in which the shifting is accomplished by hydraulic pressure developed in a hydraulic system by the weight of the forks, either loaded or unloaded, and in which the fluid pressure may be directed to move the forks selectively in opposed directions.

As a further feature of my invention I utilize means whereby power for shifting the forks may be stored.

Still another feature of the invention resides in so applying and controlling fluid bled from a load supporting ram as to operate a shift-ram at the will of the operator.

I have thus outlined rather broadly the more important features of my invention in order that the detailed description thereof that follows may be better understood, and in order that my contribution to the art may be better appreciated. There are, of course, additional features of my invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which my' dis closure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of my invention. It is important, therefore, that the claims to be granted me shall be of sufficient breadth to prevent the appropriation of my invention by those skilled in the art.

Referring now to the drawings,

Fig. 1 is a side elevation of the front end portion of an industrial truck, illustrating my invention as embodied in one form of load lifting means.

Fig. 2 is a front elevation of the load lifting means shown in Fig. 1.

Fig. 3 is a section taken along the line 3--3 of Fig. 2.

Fig. 4 is a section taken along the line 4-4 of Fig. 2.

Fig. 5 is a section taken along line 5--5 of Fig. 2.

Fig. 6 is a diagrammatic view showing the hydraulic system of my invention.

Fig. 7 is a front elevation showing a second form of my invention in which the load is adapted to be gripped by swingable arms, the gripping position of said arms beingillustrated in broken lines.

Fig. 8 is a section taken substantially along line B-8 of Fig. 7.

Referring now more particularly to the drawings, and especially to Fig. l, the front end of a lift truck, which is indicated generally by the numeral l0, has a chassis or frame H mounted on wheels, one of the front wheels being designated at l2. The constructional details of the truck are omitted from the drawings and are not described herein as they form no part of the present invention. On the usual uprights I3 which are mounted at the forward end of the frame H, is a vertically movable elevating carriage 14 having the usual vertically spaced rollers I 5 engaged with said uprights. It is to be understood that the elevating carriage l4 may be lifted and lowered on the rollers l5 by any suitable means under the control of the operator,'such as a chain It (Figs. 1 and 8).

My invention is directed to the load engaging and lifting means carried by the elevating carriage l4 and movable therewith. More particularly, the load engaging structure of my truck 50 comprises a pair of vertically spaced rods ll and I8 secured in horizontal positions on the carriage [4, upon which pair of rods is slidably mounted a fork frame 19 by means of upper and lower pairs of bearings 20 and 2!. As my load engaging members, I use a pair of lifting forks 22 and 23 attached to a connecting cross plate 24. It is to be understood that I do not wish to be limited by the particular type of lifting forks shown herein, and that other types of load engaging members may be employed with my invention.

In order to support the cross plate 24 and the forks upon the fork frame 19, provision is made of a vertical power storage ram 25, best seen in Fig. 3, which includes a cylinder 26 mounted upon said fork frame, and a plunger or piston 2? Vertically movable therein. The piston 2'! is pro vided with a ball spring valve 28 which will permit said. plSilOIlgtG be: moved. upwardly;- in: the cylinder-'26 without displacing fluidto or fromsaid cylinder.

The piston 21 of the storage ram 25 has a piston rod 32 which is fixed tothe. cross.plate..2 l,.

and since the forks 22 and 23 are attached to cross plate 24, they will move vertically with the piston 27.

ram cylinder 26 to assist upiva-rdflmovement oi the piston 21. Preferably, the force of the spring 29 is merely suificient to counteract part ef the weight of the forks 22, 23 and cross plate riage. M on the other side, and is adapted to move thefork' frame laterally along the rods i1 and [8.

As seen in Fig. 4,; an upperside portion of the carriage [4' is provided with a bifurcated' bracket member 38in whicharrapertured ear '39 on. one end of the shiftram 3lxi's pivoted by, a transverse pin 40. The lifting. fork frame l9:also:hasa--bifurcated bracket member 4i horizontally opposite the bracket member 35; A piston rod 'li2'is connected to a piston l3i.within:the shif-tram ill and is formed with an eye portion' Mlwhich is pivoted in the bifurcated bracket inembertfl'i by a transverse pin 45; Thus, it will be seen-that the lift ing forks 22'and 23 ,iandrany'lo'ad thereon-,nray be shifted laterally of'the truck: lilwhen fluid pressure is; exerted selectivelyupon either face of the piston 43. a

In order-to supply and control such fluid pressure, the shift ram-3l isprovided with apai-r of fluid conduits 4-5 and "6? connectedv thereto at opposite sides ofthe. piston 43, and the power storage ram 25. is: provided withapair of fluid conduits 48 and 49, connected thereto at oppo= site sides of the. piston, 27, a manually operable control valve -il (Fig'.. 6'). being interposed between said pairs of'conduits;

The control valve 5B=may-be-of any-suitable type which is adapted to provide-selectively reversed-connectionsbetween the respective pairs of conduits 46; il; and 48; 49 :andalso to'cut off all-flow in said-conduits. Asshown, theval-ve it comprises a rotor 5| having apair. ofv curved passages 52, 53-, which. are ec-arranged with .,re spect to the conduits that. either end of the-shift ram 31 may be connected torthetop of thepower storage. ram the opposite end of the shiftram being simultaneouslyconnected to the bottom of the powerstorage ram. A quarter. turn of the valve rotor 5! from the positionshowninFig. 6 will be effective to bring about a reversal of the ram connections, while a one-eighth turnofi the rotor will 'preventpany flow inthe.- conduits A compression. spring 29 inter posed between the lower end-M of-the piston '21" and the lower end wall of the power storage As a result of the above arrangement, the weight of the cross plate 24, the forks 22, 23, and any load thereon, will place the fluid beneath the piston 21 under pressure and thus will be effective to operate the shift ram 3'? when the control valve 58 is open. It will be noted at this point thamthe'compressionspring' 2:? will partially balancedheforks'fl and'the crossplate 24, and. will not prevent the weight of the forks and the cross plate from operating said piston. The direction in. which the shift ram 31 is operated wtlLiof. course, be determined by the positions of the valve passages 52, 53, with respect to the conduits 46,- 41,2118; 49, so that the operator may 4 utilizethe weightof the forks 22, 23, and the cross piate-M-for' shifting said forks laterally in either direction asdesiredc When the control 'valve 50 is in closed position, the lift truck It! may be operated in a conventional manner, the lifting forks 22, 23 being movable integrally with the carriage as though "the power storage 'ram- 1 were non-existent; At any time;-it is possible to develop fluid pressure with in: the storage ram as will; nowbe set-forth.-

Inorder to place-the shifting mechanism in condition for' operation; it-w-ill merely be necessary to locate-theforks 22, 23.'over a suitable abutment, and then to lower the elevating carria-ge M untiL-said forks 'engage said abutment, thedownward movement of the carriage i l-being continued for a short distanceso that the power storage cylinder-25 will descend withrelation to the -piston-2l'. This relative movement of the cylinder-25 and the'pistcnz 21 will be assisted by the spring 29; which counteracts a portion of the weight of theforks '22, 2 3, and. the cross plate 24. Inasmuch as-"the-control valve-50 will be in closed condition when thisop'eration is taking place; the'flui'ct above the" piston 27? will flow downwardly past the ball valve" 23 and. will be retained invthe cylinder -ZS-below saidv piston.

If thetruck should now-"be operated for lifting aload upon the-forks22, 23, the-weight of the load, and: at least apart ofthe weight of the forks andthecross'plate'2 l as'well, will be borne by'the fiuidbelow-the piston 21. This fluid will beutilized for shifting the forks 22, 23 laterally whenever the operator findsthat said-forks are not in the desired.lateral-alignment with a load tube pickedup=-thereby, or when: a load on the forks is not properly aligned with the space in which it :is to be'deposi-ted. It will be remembered-,-.ofwcourseythat the spring. 29 below the piston 21 preferably does not counteractentirely the weight of the forks-22, 23 and cross plate, and'this weight can therefore be utilized to shift the-forks when no load is present on-theforks.

If movement of the fork-members'to the left of the; truck is-wishedthe valve rotor 5| willbe rotated:-intothe'position shown in'Fig. c, wherein the conduits 46- and 48. will be connectedso that the fiuid-under pressure in the lower portion of. the power-storage ram 25 will be'effective to move the shift ram piston 43 toward the left of. the truck 10 (or to the right as viewed in Fig. 6') When the-=valve. rotor 5| is in the position:described,. the conduits t? and 49 are connected so that the-fluid at the opposite end of the shift ram 37- will be exhausted to the. top of the power storage. :ram cylinder 26. It will be understood that the operator may readily control. the speed'and the extent of the shifting movement by proper manipulation. of-the control: valve...

When it is desired to shift the forks 22,23,

conduit 4t is in communication with the conduit 49, and the conduit 4'! is in communication with the conduit 48. Thus, the fluid under pressure 'in the power storage ram 25 will move the shift ram piston 43-to the right (to the left in Fig. 6), and the idle fluid from the shift ram will be exhausted to the top of the power storage ram 25.

The power storage ram cylinder 26 preferably is adapted to contain a volume of fluid which is large with respect to the capacity of the shift ram 31, thus permitting repeated operation of the shift ram before the power storage ram piston 21 reaches the bottom of its stroke. When said piston does reach the bottom of its stroke, or at any other desired time, it may be restored to its upper position in the manner hereinbefore described, thus making available the fluid under pressure which is necessary for operation of the shift ram 31.

In the second form of the invention (Figs. 7

' and 8), provision is made of a pair of load engaging members or forks 54, 55, having toothed or serrated opposed portions 56, 51, for clamping a box or other load L. The forks 54, 55, are

' mounted upon the lift truck H] by means of anelevating carriage 58 to which the lifting chains [6 are connected, and which has guide rollers 59 engaged with the uprights I3 of said truck.

The front of the elevating carriage 58 is provided with upper and lower airs of bearings 60,

6I which slidably hold a pair of laterally spaced vertical rods 62, 63 attached to the back of a cross plate 64. The forks 54, 55 are mounted for lateral swinging movement upon the cross plate 54 by a pair of pivots 65 at the upper ends of said forks.

In order tooperate the forks 54, 55, for clamping'and releasing the load L, provision is made of, a hydraulic system comprising a shift ram 66, a power storage ram 51, and a control valve 68, which are connected by a plurality of conduits 69 and constructed in the same manner as described above in connection with the shift ram 31 in the'first form of the invention.

The shift ram 56, however, is pivotally connected between upper portions of the swingable forks 54, 55 by means of transverse pins 10, H,

and the ower storage ram 6? is mounted in a vertical-position upon the front of the carriage'58, thepiston rod 32 of said power storage ram being connected to an upper portion of the cross plate fluid supports the weight of the cross plate 64' and the forks 54, 55, and the opertaor may manipulate the control valve 68 so as to admit said fluid to the left-hand end of the shift ram 66 (as viewed in Fig. 7), and thus spread the forks 54, 55 apart.

If the truck i0 should now be maneuvered to bring the forks 54, 55 into positions at opposite sides of the load L, as illustrated in Fig. '7, the control valve 68 may be operated to cause the fluid under pressure from the power storage ram 6 61 to enter the opposite end of the shift ram 66 and thus cause the forks 54, 55 to grip the load L, as shown in broken lines in Fig. '7.

The elevating carriage 58 and the truck 10 may now be operated to lift and transport the load L to the desired location, the control valve 68 preferably being left in such a position that the fluid pressure in the right-hand end (Fig. 7) of the shift ram 66 will be maintained by the power storage ram 61. When the control valve is in this position, it will be seen that the added weight of the load L will act through the power storage ram 5! and will increase the clamping force of the forks 54, 55.

When it is desired to release the load L, it will merely be necessary to reverse the action of the fluid in the shift ram 66 by manipulating the control valve 58.

When the piston 21 approaches the bottom of the power storage ram El, as will occur after the shift ram 65 has been operated a number of times, the operation of engaging the forks over an abutment and lowering the carriage 58 will be repeated in the manner hereinbefore described, thus restoring the lower portion of the power storage ram with a quantity of fluid which will be available for operating the shift ram.

Having thus described the invention, what is claimed as new and for which it is desired to secure Letters Patent is:

1. In a lift truck of the class described, a lifting carriage, a loadengaging member, means engaging member to the piston, a shift ram for shifting the load engaging member, a valve, fluid passage means between said valve, said shift ram and said power storage ram whereby fluid under pressure of the loadmay be directed from one end of said storage ram toward'one-end or the other of said shift ram, said valve directing to the other end of the power storage ram the fluid from that end of the shift ram opposite the end to which said fluid under pressure is directed, and a passage through which fluid flows from one end of said storage ram piston to the other end of said storage ram piston when the load engaging member moves-upwardly on its mounting means relatively to the lifting carriage,

2. In a lift truck of the class described, a lifting carriage,- a load engaging member, means mounting said load engaging member on said carriage for movement relativelythereto, a hydraulic power storage ram having a piston, means for applying the weight of a load on the load engaging member to the piston, a shift ram for shifting the load engaging member, a valve, fluid passage means between said valve, said shift ram and said power storage ram whereby fluid under pressure of the load may be directed from said power storage ram toward one end or the other of said shift ram, said valve directing to the power storage ram the fluid from that end of the shift ram opposite the end to which said fluid Iunder pressure is directed, and said power storage ram having a fluid capacity that is large relatively to the fluid capacity of the shift ram whereby sag-seams 7 rreiativcly tozsaid frame;.a:lifting;carriage, means i mounting: saidczframe ionlateralemovementrelatively to saidicarriage'whereby said'load: en a n timemben-zalsom-moves laterally, .--a;. ram inter-posed abetweenwsaid load engaging member; and said flirameswith fluid in said ram placed under-presssnrehy said 110311 engaging member a second ram :Qinterposed :between said frame and.- said carriage i -for imparting relative. movements-between .said

framaand carriage, fluid passage means through :.,.to said, lifting carriage, a second hydraulic ram; .nmeansiinountingi said second. hydraulic. ram.on

saidol-iitingc, carriage. wherebyrsaidisecond ramis adapted to operate load manipulatingmechanism .on said carriagejfluid passage, means through whichfluid is'directed fromflthe, first ram toward .onenendorv the other of the second ram whereby "the weight of l,the loadgonJthe carriage :acts ;,through, said fluid? for actuating the, second ram ;,and operating said load manipulating? mechanism, said fluid passage means returning toi'thefirst ram exhaust i fluid from that end :of ;the second ram opposite that endto whichthe'fluid ;flws from the first rain, and a valve for the fluid insaid .passagetmeans to control the movements imparted by'the'weight or the load totheisecon'd :"ram.

51in ailift truck or" theclassdescribe'd; a lift- --ing marriage, a "first .hydraulic tram, "means whereby said firsthydraulicram supports-a load --rela-tively tosaid lifting -carriage, a; second -hy- -dra-ulic1-ram, "means through which: said second hydraulic ram 'when actuated operates mechanism on the'truckffluid-passagemeans through "which fluid is directed'fromone'end of thefirSt -ram: toward one end or the otherofthesecorid ram'whcreby the weight of the load on thecar- *riage -acts through said fiuid 'for actuating'the secon'd ram in either-of two directionsfor opereating said mechanism, said fiuid 'passage' means ---returning tothe other end of the first ram-' exhaust fluid from that-endof the'secondramop- ,posite the'end to-=which the fluid flows from the first ram, and valve means for directing 'the flow of the said fluid in said'passage means.

'BJJIn a"-1ift tru'ckof the class describedga 'liit- -ing carriage, .-a :first hydraulic ram, 'means w-herebysaid first hydraulic. ram supports a load relativjely to said lifting carriage, a ,hydraulic zshift -ram, means through which said shift 'ram is=adapted to act for shifting: the load relatively rotor said carriage, "fluid passage means -through -:.:which fluid is directed from the firstram' toward oneien'd or the otherof the shift ram whereby azthe :weight of the load on the carriage facts rthrough'sai'd fluid for actuating'the shiftrampand shifting the t load, said fluid passage :rmeans :L'returning to the. first ram= exhaustfluidrfrom: that r-cnd of :the shift ram: opposite that end rto which =;the rfluidzfiows fromthe first ram, and -valve rmeans ior' directingv the flow of the: said fluidin r'saidpassage means. 57.111 a .lift truck :of the :class "described, ;a lifting carriage, a first hydraulic ram havingz-a pistcn, means whereby said first hydraulic ,iram sddwmfisiflz-lo d;relativelyrto;saidgliftingzcarriage avithsthe weightzof the load a placing-under ipres- -zsure it fluideat:zonesend of? saidivpistonn hydraulic: ram;meanstmountingesaidz' secondihy- Edraulic ram: on said; lifting:carriagewherehyesaid --second' ram is:ada-pted to operaterloadmani-pulatingmechanism 'on said :carriage fluidgpassage :means through which fluid is directed from the said onerendof therpiston-in-the first ram toward one-end or the othenof thetsecond' ram-whereby the weight 1 of I the =-load won the carriage zacts Y throughsaid ,fiuid? foraactuatingthesecond ram and operating. said :load manipulating .cmebhavnism, said. fluid passage; means returning toe-the first ram exhaust fluid from that end rofc-theisec- 0nd ram'opposite thatendto-fwhich the fluidflows from the first ram and valve means foridirecting the flow. of thesaid fiuideinisaidpassagea-means. 8. i In a lift truck of-the classdescribed, a lifting carriage,.-.a first hydraulic ramr-havingsa piston, means whereby said firsthydraulic ramsupp rts a load relativelyito' said liftingecarriagewiththe weight of the load placing under pressure tluida'it one. end. of.- said piston a. second -hydraulic ram, means through which said. second hydraulic: ram whenactuated operates mechanismnon the-truck,

25 fluid. passage means .through whichfiuidlisdirected from said. one end. of =the,,-pistonn ina'the .first ram toward one .endcor the other ofuthe second ram whereby the weight .of the" load ionltthe carriage acts through-said fluid for actuating the second ram in either of.two directions-inoperating said mechanism, said'fiuid passage Smeans returning to the opposed' endof the pistondn the ffirst ram exhaust fluid'from thatien'd of'the second ramiopposite thatend to which the 'fluidlflows fromfthe first ram, valve means'foridirectingi'the flow of the Zfluid in said passage means, and ;\-a passage independent ofsaid valve means whereby fiuidflows' from the said opposed end of thepiston to the said. oneend of the piston to'permit'ifree movement of 'said piston in:one"direction"in" said *first hydraulic ram.

."9."In1a lift truck'of the class described, alifting carriagaa first hydraulic ram, meanswhereby said'first hydraulic ramsuDDOrts a load relatively to said. lifting carriage, a; hydraulic .shiftr ram,

means through Whichasaidi shiftramvisi adapted to v act .for shifting .,the -load relatively to asaid .v carriage, fiuidpassage meanathrough-which:fluid is directed from one :end -of.the first-ram: toward one :end A or the other: of ethewshiftl ram whereby =:the weight ,Of the -load on the :carriageiacts r throughsaid fluid: forractuatingithe shift v ramtin either of twozdirections fonshifticngatheloaidmnd valve means for directing the flow of the said TLOQIIl a lift'rtruck of the class descr ibedsa liiting carriage, a first hydraulic-rant having apiston,

' means wherebysaid first hydraulic ram supports *a' load relatively to said lifting carriagewithi'the weight of the load placing under: pressure 'fluid at one end of said piston; a secondhydraulic ram,

imeans through which-said secondi'h draulicram when actuatedoperates'mechanism on't'hetruck,

second ram in either of two directions fonopera-tling .sa-id mechanism, said I fluid passage :ameans return-ingto theopposed endi'of the pistonim the 1 first ram fluid exhausted 1 from 2 that weird of i the isecondziram opposite thatuend towhich thetflnid fiowstfrom the i-said rone endz'of thei plstonfiand 9 valve means for directing the flow of the said Number fluid in said passage means. 2,560,438 2,571,550 References Cited in the file of this patent 2,575,552 UNITED STATES PATENTS 5 2, 3 95 Number Name Date gg ggi 2,038,974 Werner Apr. 28, 1936 2,370,528 Fontaine Feb. 2'7, 1945 2,509,023 Vogel et a1 May 23, 1950 10 Numbef 2,536,151 Backofen et a1 Jan. 2, 1951 575,488

Name Date Gunn, Jr July 10, 1951 Ehmann Oct. 16, 1951 Glenn, Jr Nov. 20, 1951 Frischmann May 13, 1952 Seagraves et a1 July 1, 1952 Shaffer Dec. 23, 1952 FOREIGN PATENTS Country Date Great Britain Feb. 20, 1946 

